Building a new block chain against quantum computing
blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies
blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
extended data
according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:
1. The blockchain with the whole network open and without user authorization mechanism is called public chain
2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain
3. All the nodes in the network are in the hands of one organization, which is called private chain
alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain
blockchain features
1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes
5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously
One of the characteristics of blockchain projects (especially public chains) is open source. Through open source code, to improve the credibility of the project, so that more people can participate. But the open source code also makes it easier for attackers to attack blockchain system. In the past two years, there have been a number of hacker attacks. Recently, the anonymous currency verge (xvg) was attacked again. The attacker locked a vulnerability in the xvg code, which allowed malicious miners to add false timestamps on the block, and then quickly dig out new blocks. In a few hours, the attacker obtained nearly $1.75 million worth of digital currency. Although the subsequent attack was successfully stopped, no one can guarantee whether the attacker will attack again in the future
of course, blockchain developers can also take some measures
one is to use professional code audit services,
the other is to understand the security coding specifications and take preventive measures
the security of cryptographic algorithm
with the development of quantum computer, it will bring a major security threat to the current cryptosystem. Blockchain mainly relies on elliptic curve public key encryption algorithm to generate digital signature for secure transactions. Currently, the most commonly used ECDSA, RSA, DSA, etc. can not withstand quantum attacks in theory, and there will be greater risks. More and more researchers begin to pay attention to cryptographic algorithms that can resist quantum attacks
of course, in addition to changing the algorithm, there is another way to improve the security:
refer to bitcoin's treatment of public key address to rece the potential risk of public key disclosure. As users, especially bitcoin users, the balance after each transaction is stored in a new address to ensure that the public key of the address where bitcoin funds are stored is not leaked
security of consensus mechanism
the current consensus mechanisms include proof of work (POW), proof of stake (POS), delegated proof of stake (dpos), practical Byzantine fault tolerance (pbft), etc
POW faces 51% attack. Because POW depends on computing power, when the attacker has the advantage of computing power, the probability of finding a new block will be greater than that of other nodes. At this time, the attacker has the ability to cancel the existing transaction. It should be noted that even in this case, the attacker can only modify his own transaction, but not the transaction of other users (the attacker does not have the private key of other users)
in POS, attackers can attack successfully only when they hold more than 51% token, which is more difficult than 51% computing power in pow
in pbft, when the malicious nodes are less than 1 / 3 of the total nodes, the system is secure. Generally speaking, any consensus mechanism has its own conditions. As an attacker, we also need to consider that once the attack is successful, the value of the system will return to zero. At this time, the attacker does not get any other valuable return except destruction
for the designers of blockchain projects, they should understand the advantages and disadvantages of each consensus mechanism, so as to select an appropriate consensus mechanism or design a new consensus mechanism according to the needs of the scene
security of smart contract
smart contract has the advantages of low operation cost and low risk of human intervention, but if there are problems in the design of smart contract, it may bring greater losses. In June 2016, the Dao, the most popular funding project of Ethereum, was attacked. The hacker obtained more than 3.5 million Ethereum coins, which later led to the bifurcation of Ethereum into Eth and etc
there are two aspects of the proposed measures:
one is to audit the security of smart contract, and the other is to follow the principle of smart contract security development
the security development principles of smart contract are: to be prepared for possible errors, to ensure that the code can correctly handle the bugs and vulnerabilities; Release smart contracts carefully, do well in function test and security test, and fully consider the boundary; Keep smart contracts simple; Pay attention to the threat intelligence of blockchain and check and update in time; Be clear about the characteristics of blockchain, such as calling external contracts carefully
security of digital wallet
there are three main security risks in digital wallet: first, design defects. At the end of 2014, a user lost hundreds of digital assets e to a serious random number problem (repeated r value). Second, the digital wallet contains malicious code. Third, the loss of assets caused by the loss or damage of computers and mobile phones
there are four main countermeasures:
one is to ensure the randomness of the private key
The second is to check the hash value before installing the software to ensure that the digital wallet software has not been tampered with The third is to use cold wallet The fourth is to back up the private keylegal representative: Xu Rong
time of establishment: April 28, 2018
registered capital: RMB 10 million
enterprise type: limited liability company (invested or controlled by natural person)
address: 205, building 3, No. 6, Jiapin third Street, Shatou street, Panyu District, Guangzhou City
Blockchain is a new technology, not a disguised form of MLM. It is just claimed by many MLM organizations as "blockchain". In fact, there is no technology. It's just a practice of MLM under the name of "blockchain". The state has issued several announcements to crack down on this kind of MLM. The following is the Xinhua news report on MLM of blockchain:
blockchain is not equal to virtual currency, but also has security risks. Behind the popularity, there is exaggeration with "ulterior motives". Only by removing the flashiness, can the blockchain return to its real application value
invest 80000 yuan, change to 800000 yuan after three months? Shenzhen police cracked a huge fund-raising fraud. Under the guise of blockchain concept and 10 times income, thousands of investors were deeply involved in the case, involving up to 307 million yuan. Under the "veil of mystery" of the blockchain, the illegal elements have taken advantage of their own tricks, and the blockchain has become a "signboard" of economic crimes such as fraud and pyramid selling
why is the blockchain repeatedly "misused" by illegal activities such as pyramid selling fraud? In addition to "unknown", what is the "function" of blockchain technology itself? Since the beginning of this year, with the increase of supervision and the cooling of currency speculation, new opportunities have been brought to the development of blockchain. How about the implementation of blockchain commercial "application" The reporter of outlook news weekly recently concted an investigation
when the three-month "capital release period" promised by the trading platform expired and the staff began to "kick" in the QQ group, Tang Haiyan, who lives in Bao'an District of Shenzhen City, realized that she might have been cheated
previously, Tang Haiyan invested 80000 yuan to buy a virtual currency called "ordinary silver coin" under the introction of her classmates“ The other side said that this currency is the most advanced blockchain technology at present, with Tibetan tea as collateral. He also showed me the "technical white paper". I didn't understand blockchain, so I didn't read it carefully. "
although she doesn't know about blockchain and virtual currency, the high investment income makes Tang Haiyan full of expectations. She told reporters that companies issuing "ordinary silver coins" will regularly split the virtual currency according to the ratio of 1:10, which means that each split will make the value of "ordinary silver coins" in the hands of investors expand 10 times. As long as after a split, her investment of 80000 yuan is equivalent to the purchase of 800000 yuan worth of "ordinary silver coins", which can be sold on the trading platform to obtain huge profits
according to the rules of the trading platform, the newly purchased "ordinary silver coin" cannot be traded immediately, and it must be frozen on the platform for three months before it can enter the "release period". However, after three months, not only did Tang Haiyan not wait for the assets to double, but the 80000 yuan frozen on the platform could not be used for trading
"other investors began to question the authenticity of this investment in QQ group. As a result, the staff of the company kicked these investors out one by one, which made me feel bad." She said
The fact also proves Tang HaiYan's intuition. At the end of March 2018, Shenzhen police detected a huge fund-raising fraud, with the amount of fraud funds as high as 307 million yuan. In this case, Shenzhen Puyin blockchain Group Co., Ltd. involved in the case issued virtual currency in the mode of "blockchain + Tibetan tea" to obtain public deposits. Tang Haiyan was one of the thousands of victimsShenzhen police investigation found that the company claimed that investors could buy and sell "ordinary silver coins" on the virtual trading platform "jucoin net" to earn a price difference
. In fact, the change of its trading price is that the company used investors' investment funds for behind the scenes operation, and once raised the price of "ordinary silver coin" from 0.5 yuan to 10 yuan, so that investors can taste some sweetness. When a large number of investors entered the market, the company continued to cash out through malicious manipulation of the price trend of "ordinary silver coin", which eventually led to the worthlessness of "ordinary silver coin" in the hands of investors
since 2018, engaging in fraud and pyramid selling under the banner of blockchain has become a common "routine" in new criminal tactics. In April 2018, Jinan police dropped a pyramid selling Gang under the guise of "western development", "national poverty alleviation", "original stocks", "blockchain" and "e-commerce", arrested more than 10 major suspects, frozen more than 100 accounts involved, and seized more than 300 million yuan of funds involved
according to Jinan police, huileyi e-commerce company designed a fake virtual disk on the Internet on the ground that the country is vigorously developing the big data instry, and released a variety of virtual currencies such as "precious currency" and "precious currency"
under the guise of giving away, they presented a certain amount of virtual currency to the New MLM staff, with the price of tens of yuan each. Then, through artificial manipulation, they appreciated the virtual currency all the way to more than 100 yuan or even hundreds of yuan, attracting people who did not know the truth to join. Finally, they "cut leeks" through the periodic fluctuation of the so-called "devaluation" of virtual currency, Finally, the purpose of seeking illegal interests is achieved
in Xi'an, a few days ago, the local police successfully cracked a huge network pyramid selling case under the banner of blockchain. According to the police, the suspect, Zheng Mou, has paid a high salary to the 9 network members, such as Zhang and Lee. Since March 28, 2018, he has gathered pyramid selling and network pyramid selling as a means to sell the virtual Datang coins at the consumption era network platform at the price of 3 yuan each, and manipulate the appreciation rate; p>
at the same time, promotion meetings were held in many cities at home and abroad to attract members. According to the development of members, 28 level agents were set up. In just 18 days, the gang developed more than 13000 registered members. At present, it has been found that the case involves 31 provinces, cities and autonomous regions in China, and the fund involved is as high as 86 million yuan
according to Tencent's 2017 pyramid selling situation awareness white paper released by Tencent security joint laboratory, in recent years, all kinds of overseas capital disk, virtual currency and ICO (initial public offering token financing of blockchain project) projects have emerged in an endless stream, which hide many risks such as illegal issuance, untrue projects, cross-border money laundering, fraud and pyramid selling, As a result, a large number of funds flow overseas. Once the market collapses, runs away or loses contact, investors often have no way to complain and the losses are difficult to recover. For example, Baichuan coin, mark coin, beta coin, dark coin, etc
the reporter of lookout Newsweek interviewed in Guangdong, Shandong, Shanghai and other places and learned that most people know that the concept of blockchain is very popular, but they "don't know where it is", and there are different opinions on the specific functions of blockchain: some people think it is used for "investment and financing", "buying and selling currency", while others think it is "a major invention of the same magnitude as the steam engine", Some entrepreneurs are even more eager to seize this "once-in-a-lifetime opportunity to get rich."
many people in the instry said that it is precisely because people have many misunderstandings about blockchain that criminals have opportunities to fish in troubled waters and mislead investors
First, blockchain is not equal to virtual currency. By the end of last year, the number of domestic ICO participants and the total volume of transactions have doubled, a large number of digital currency exchanges have fled overseas, and the agent investment mode has involved more ordinary people in high-risk investmentin many instries, we media and celebrities form interest alliances with issuers and digital exchanges to endorse and create public opinion for the "air currency" project. In December last year, nine departments including the people's Bank of China identified ICO as "suspected of illegal fund-raising, financial fraud, pyramid selling and other illegal and criminal activities"
in the interview, many people told our reporter that the existence of token has built a set of rights and interests mechanism for the development of blockchain technology, which is indispensable for stimulating the prosperity of blockchain applications“ The market practice in the past five years has proved that blockchain applications without equity mechanism are just like market economy without computers connected to the Internet and money, with greatly reced application scenarios and development speed. " An investor in Shanghai said
in fact, the token represented by bitcoin is only one of the earliest procts to verify the blockchain technology, and the two can not be equated, and the existence of token has obviously negative effects on the development of blockchain
Xiao Wei, chief engineer of network blockchain, told this reporter that the myth of ICO's sudden wealth shakes the R & D concentration of blockchain technical talents, and the myth of "sudden wealth" with hundreds of times of return tests the patience of blockchain technical R & D talents“ Many of the "comrades in arms" in the circle who used to do research and development of blockchain technology have gone to issue coins, and now few of them can insist on doing research and development and application of technology. "
Xu zewei, Secretary of the Party committee of Beijing Internet Finance Instry Association, said that under the background of China's ban on ICO, many domestic start-ups promoting blockchain applications are "selling dog meat with sheep's pawn" and financing through concept packaging of worthless tokens“ ICO has polluted the good atmosphere of innovation and entrepreneurship, and created a kind of speculative proct. Many young people are not thinking about entrepreneurship, but are thinking about issuing money, which makes us have the illusion of getting rich overnight. "
at present, more and more people in the instry begin to think about whether the development of blockchain must rely on the issuance of tokens to achieve incentives. Guo Dagang, Secretary General of Beijing Internet Finance Instry Association, told this reporter that the so-called incentive mechanism is only the theoretical basis for the project party to issue tokens for itself. Huo Xuewen, director of Beijing Municipal Bureau of financial work, also believes that if blockchain does not get rid of the dilemma of issuing currency, it will never find a legal landing mechanism
secondly, blockchain is not omnipotent and its security is at risk. Blockchain is generally considered to achieve three functions:
first, the data stored on the blockchain can not be tampered or forged, and the data has high credibility and credibility; Second, the whole process of the transaction can be traced, which can achieve accurate responsibility tracking; Third, the embedded smart contract in the blockchain can be executed automatically based on the contract, so as to improve work efficiency and rece the risk of default. It is generally believed that blockchain has broad application prospects in finance, logistics, trade and other fields
in fact, blockchain is not omnipotent, and its function has many limitations. It is generally believed that, according to the characteristics of cryptography, in order to tamper or falsify in the blockchain, more than 51% of the nodes need to be controlled in theory. When there are enough nodes in the blockchain, it is difficult to tamper with the trust creation mechanism widely participated by the public
However, in reality, digital currency exchanges are frequently attacked or even stolen. On June 20, 2018, bithumb exchange of South Korea announced on its official website that the exchange had been attacked by hackers and stolen 35 billion won, about 32 million US dollars of cryptocurrency Ji Xinhua, known as the first generation of "hackers" in China, said that the blockchain will continue to face attacks, and the process of uploading data to the blockchain is prone to information leakage. Some people in the instry worry that once the super computing power of quantum computing is realized, it will also have a direct impact on the blockchainZhao Yao, a special researcher of the Institute of finance of the Chinese Academy of Social Sciences, told this reporter that the academic community has confirmed as early as 2013 that the blockchain is not perfect and there are many "cheating" strategies. As long as there are enough economic incentives, controlling attacks of more than 51% nodes does not only exist in theory
Zeng Guang, Secretary General of Shenzhen Internet Finance Association, said that the blockchain technology itself does not have the ability to do so
in fact, in the real world, even if quantum computing is implemented, if the topology of the whole network is still in accordance with the existing model (the infrastructure will be updated for many years), quantum computers can only greatly improve the computing power on a few nodes and obtain accounting rights, So basically, quantum computing should be safe before it reaches everyone's personal computer.
1. If the deposit is entrusted to the agent of the deposit unit, the agent of the deposit unit shall issue the original and of his ID card and the of the client's ID card at the same time
2. For entrusted spouse, parents and children, the agent shall issue the original and of his / her ID card, the original and of the client's ID card, and the original and of valid relationship certificate (such as marriage certificate, household register with the same address or relationship certificate issued by the police station)
3. If the agent entrusts another person to handle the matter, he / she shall issue the original and of his / her ID card, the of the client's ID card, and the original and of the notarial certificate of deposit issued by the agent.